As is well known, a non-volatile memory is able to continuously retain data after the supplied power is interrupted. Consequently, the non-volatile memory is widely used in a variety of electronic products. Generally, the non-volatile memory comprises a memory cell array. The memory cell array consists of plural memory cells. In addition, each memory cell has a floating gate transistor.
In a program mode, a high voltage is received by the memory cell array. Consequently, hot carriers are injected into the floating gate of the floating gate transistor of a selected memory cell.
Moreover, in an erase mode, the high voltage is also received by the memory cell array. Consequently, the hot carriers are rejected from the floating gate of the floating gate transistor of the selected memory cell.
That is, in the program mode and the erase mode, the high voltage is received by the memory cell array to control the hot carriers to be injected into or rejected from the floating gate of the floating gate transistor. Consequently, the non-volatile memory has a voltage switch circuit for providing different operating voltages to the memory cell array according to different working modes.
Generally, the above high voltage (e.g. 18V) is much higher than the voltage level (e.g. 5V, 3.3V or 1.8V) of the general logic circuit. Consequently, the voltage switch circuit should be specially designed in order to be applied to the non-volatile memory.